In recent years, various types of content, such as video, sound, and text, are being delivered. Standardization of the transport format for delivering such content is also advancing. In particular, standardization of MPEG media transport (MPEG MMT) protocol is gaining attention.
In MPEG MMT, standardization is advancing for a transport format and the like that efficiently deliver a plurality of components, such as video, sound, and text, over differing paths (hybrid delivery).
The content in MPEG MMT is stored as a package (MMT package) and includes, in addition to a plurality of components (MMT assets), at least data related to composition information (CI) and transport characteristics information (TC). The composition information indicates reproduction conditions, such as layout including display position, size, and the like of each component, and whether or not components can be combined. The transport characteristics information includes required bandwidth, allowable delay, and the like of each component, used to determine the optimal delivery path.
The components included in such content can be divided into packets and transported over a single network, or transported over a plurality of networks (hybrid). This will be described with reference to FIG. 14. FIG. 14 is a diagram of content transport formats. FIG. 14(a) shows an example of transport over a single network. FIG. 14(b) shows an example of hybrid transport over a plurality of networks. In FIG. 14, a single transport packet is indicated by a single block.
In the example in FIG. 14(a), a transport packet CI for configuration information and a transport packet TC for transport characteristics information are followed by a plurality of transport packets (A1,1, A2,1, . . . ). Transport packet A1,1 and subsequent transport packets Ai,j: i=1, 2, . . . , j=1, 2, . . . ) each include a media unit composing an asset. These media units are transmitted to a receiver over a network determined based on the TC, and the receiver reproduces these media units based on the CI.
In the example in FIG. 14(a), all transport packets are delivered from a transmitter to a receiver by a single path over a single network.
On the other hand, in the example in FIG. 14(b), transport packets (A2,1, A2,3, . . . ) and (A2,2, A2,4, . . . ), obtained by dividing into two a transport packet A2,j including a media unit composing a second asset, and transport packets (A1,1, A1,2, . . . ) including media units composing a first asset are each transported on differing paths over differing networks. The hybrid transport is also described in PTL 1, below.